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为了研究拱形钢塔在施工阶段和成塔状态时的风致振动控制方法,建立了之江大桥施工及成塔状态的拱形钢塔有限元模型,采用改进谐波合成法模拟了脉动风荷载并作为输入,对加设MTMD的施工及成塔状态的钢拱塔进行了动力时程分析。利用ANSYS参数化设计语言(APDL)编制了计算程序,以精确求解钢拱塔顶部的最大位移与加速度的减振率,进而对MTMD系统进行了参数分析,研究了质量比μ、TMD的数量m、阻尼比ξT和带宽β对MTMD系统减振效果的影响,并得到了最优化的参数值;并设计了可控制钢拱塔面内(施工)与面外(成塔)振动的MTMD系统,提供了工程施工所需的具体设计参数值。研究结果表明:当钢拱塔从施工状态变为成塔状态时,其基阶振型也由面内振动转变为面外振动,在这体系转换过程中,钢拱塔容易发生风致振动;建议了施工和成塔状态的MTMD系统的最优参数值,即μ=0.01、m=12、ξT=0.05、β=0.1(施工)和β=0.2(成塔)。所设计的可转动的MTMD系统可以有效地控制钢拱塔的风致振动响应,并可为同类工程的建设提供科学依据和参考。
In order to study the wind-induced vibration control method of arch steel tower during construction and towering, a finite element model of arch steel tower with construction and towering condition of Zhijiang Bridge was established. The modified harmonic synthesis method was used to simulate the fluctuating wind load And as input, the dynamic time history analysis of the steel arch tower with MTMD construction and towering state was carried out. Using ANSYS parametric design language (APDL), a calculation program was compiled to accurately calculate the maximum displacement and acceleration damping rate at the top of the steel arch, and then the MTMD system parameters were analyzed. The mass ratio μ, the number of TMD m , Damping ratio ξT and bandwidth β on the damping effect of the MTMD system are obtained, and the optimal parameter values are obtained. The MTMD system which can control the vibration in the steel arch (in-plane) and in-plane (tower) Provide the specific design parameters required for construction. The results show that when the steel arch tower changes from the construction state to the towering state, the fundamental mode shape changes from the in-plane vibration to the out-of-plane vibration. During the conversion process, the wind-induced vibration is likely to occur in the steel arch tower. The optimal parameters of the MTMD system for construction and towering are μ = 0.01, m = 12, ξT = 0.05, β = 0.1 (construction) and β = 0.2 (towering). The designed MTMD system can effectively control the wind-induced vibration response of the steel arch and provide a scientific basis and reference for the construction of similar projects.